Real-time Infrared Satellite over Land

Infrared satellite images of Earth, taken from a vantage point high in
the sky, reveal the formation and movement of clouds across the planet.

Infrared satellite images are used by meteorologists to determine where
clouds are, but more importantly, how the clouds are moving. The infrared
satellites work by measuring the infrared radiation that is emitted. Because
the emitted radiation is proportional to temperature, the data are converted
to temperature values. In comparison to clouds, the Earth's surface, even
on very cold nights, is warm. When there are clouds, they absorb the radiation
emitted by the Earth below and emit their own radiation at a much cooler
temperature. Any area that has clouds shows up cooler than the ground, allowing
meteorologists to detect the locations of the clouds.

The height of clouds is inversely proportional to temperature,
meaning that the tallest clouds are the coldest. It is often
the tallest clouds that bring the most severe weather. In this animation,
the lowest clouds are a very light gray and the highest clouds are bright
white.